[Qemu-devel] [PATCH v8 3/6] s390x/kvm: enable/disable AP instruction interpretation for guest

[Tony Krowiak]

From: Tony Krowiak <address@hidden>

Let's use the KVM_SET_DEVICE_ATTR ioctl to enable or disable
hardware interpretation of AP instructions executed on the guest.
If the S390_FEAT_AP feature is installed, AP instructions will
be interpreted by default; otherwise, they will be intercepted.
This attribute setting may be overridden by a device. For example,
a device may want to provide AP instructions to the guest (i.e.,
S390_FEAT_AP turned on), but it may want to emulate them. In this
case, the AP instructions executed on the guest must be
intercepted; so when the device is realized, it must disable
interpretation.

Signed-off-by: Tony Krowiak <address@hidden>
---
 target/s390x/kvm.c |   16 ++++++++++++++++
 1 files changed, 16 insertions(+), 0 deletions(-)

diff --git a/target/s390x/kvm.c b/target/s390x/kvm.c
index c4bd84d..28a3900 100644
--- a/target/s390x/kvm.c
+++ b/target/s390x/kvm.c
@@ -2297,6 +2297,19 @@ void kvm_s390_get_host_cpu_model(S390CPUModel *model, 
Error **errp)
                S390_FEAT_MAX);
 }
 
+static void kvm_s390_configure_apie(int interpret)
+{
+    uint64_t attr = KVM_S390_VM_CRYPTO_DISABLE_APIE;
+
+    if (interpret) {
+        attr = KVM_S390_VM_CRYPTO_ENABLE_APIE;
+    }
+
+    if (kvm_vm_check_attr(kvm_state, KVM_S390_VM_CRYPTO, attr)) {
+            kvm_s390_set_attr(attr);
+    }
+}
+
 void kvm_s390_apply_cpu_model(const S390CPUModel *model, Error **errp)
 {
     struct kvm_s390_vm_cpu_processor prop  = {
@@ -2346,6 +2359,9 @@ void kvm_s390_apply_cpu_model(const S390CPUModel *model, 
Error **errp)
     if (test_bit(S390_FEAT_CMM, model->features)) {
         kvm_s390_enable_cmma();
     }
+
+    /* configure hardware interpretation of AP instructions */
+    kvm_s390_configure_apie(test_bit(S390_FEAT_AP, model->features));
 }
 
 void kvm_s390_restart_interrupt(S390CPU *cpu)
-- 
1.7.1